Best way to Vent storage tank?

[Garycw]

Just got a 100 gal tank for deisel from tsc. When I got home with it and removed cap it almost blew out of my hand. The H100 hand pump I'll be using says use with vented tank. The vented caps seem pricey and wanted to know if I could just drill a small hole in existing cap? The tank will be stored inside a barn.

 

[s219]

Home heating oil (same as diesel) tanks have a very simple vent, so it's certainly reasonable for a tank that stays put and doesn't need to move. I'd only want a proper spring loaded vent cap for any type of "transfer" tank that will be moved.

If you are going to use a transfer pump to fuel up a tractor from the tank, the vent will have to be fairly substantial. A small hole drilled in the cap won't be enough to vent fast enough. Instead, can you put threaded black iron pipe (don't use galvanized) into the fill port, or another tapped port on top of the tank, and run up and turn back down with an elbow? Or just get a vent stack from a home heating oil tank.

 

[Garycw]

Yes I do remember my old fuel oil tank did have a little vent on it. When filling tractor I could just loosen cap for flow. In just concerned about tempeture changes for pressure & vacuum in the tank. I don't have any other fittings on tank other than cap and pump fitting

 

[aczlan]

Could find an oil filter with npt threads and install that on the vent. That will keep the nasties from getting in via the vent.

Aaron Z

 

[hosspuller]

Check the cap. It should have a a rubber gasket that moves. It vents both pressure and vacuum. Maybe the rubber got stuck together in storage. A little oil on both sides should prevent that happening.

You DO want some resistance to pressure changes. It slows the exchange of moisture ladden air into the tank. Just loosen the cap when you're pumping out of the tank. :thumbsup:

 

[SandburRanch]

A common vent is a pipe bushing xx ( bung size ) x 1/4" bushing with a 1/4" pipe to compression tubing fitting with the copper tubing riser bent 180° or 2 90° bends. Works for indoors or outdoors.

 

[Garycw]

The only problem is I have only two openings. One for cap one for pump. I guess I could do away with cap and use a removable vent for filling

 

[SandburRanch]

Vent the cap by drilling and tapping 1/4" pipe threads.

 

[Gary Fowler]

By what ever means that you have at your disposal, tap into the vent cap with a 180 degree bend from the cap. You can use 1/4" tubing or pipe but the end needs to be covered with fine screen to keep spiders and dirt daubers out of the pipe. I 180 degree bend will keep any water from entering. You will still have the moist air coming in and going out as temps raise and fall so condensation may be an issue.

I don't vent my rectangular tank at all. The fill point has a gasket that keeps moisture from getting in. It may not be totally air tight but sometimes I hear the tank sidewalls collapse in at night when it cools off rapidly. Mostly it just sets in the corner of my shop totally silent and the pump has never had a problem PLUS I don't have any condensate in the tank after over 5 years of use.

 

[doxford jim]

I have an open (fine metal screen) ended vent on my diesel tank, which sits inside a shed. Never had a moisture problem yet in ten years use. Make sure you have a way of draining off water from the tanks in case you need it - a low drain cock. Water will separate out from diesel if left undisturbed (different specific gravities). Make a point of checking this drain (for water) on a regular basis and you should be good to go.